Field of the Disclosure
The technology of the disclosure relates to a hydraulic fuel pump apparatus for a fuel delivery chassis, such as an aircraft fuel delivery vehicle.
Technical Background
Fuel pumps and fuel dispensers are used to dispense fuel to vehicles and other equipment requiring fuel for operation. The basic components of a fuel dispenser are as follows. The fuel dispenser contains a fuel conduit that receives fuel from a fuel source and directs the received fuel to an outlet to be dispensed into desired equipment when the fuel dispenser is activated. A pump, either self-contained within the fuel dispenser or located outside the fuel dispenser and coupled to the fuel conduit, provides the pumping force to direct the fuel through the fuel dispenser when activated. Once the fuel is pumped into the fuel conduit inside the fuel dispenser, it encounters a number of fuel handling components located inline the fuel conduit, before eventually being delivered. For example, the fuel encounters a meter to measure the amount of fuel being dispensed. A fuel flow control valve is located inline the fuel conduit either on the inlet or outlet side of the meter, to control whether the fuel is allowed to pass through the fuel conduit to the outlet of the fuel dispenser. The outlet of the fuel dispenser is typically comprised of a flexible hose that is coupled to the fuel conduit on one end and to a nozzle on the other end. A user engages a nozzle handle trigger to allow fuel to flow. The nozzle also contains its own fuel flow control valve that is trigger-activated by the user.
An example of a fuel dispenser that is employed in the aviation industry, in particular for fueling aircraft, is illustrated in FIG. 1A. As shown, a fuel delivery vehicle 10 is provided that contains a fuel delivery assembly 12 installed on a vehicle chassis 14. The fuel delivery vehicle 10 is mobile so that the fuel delivery assembly 12 can be conveniently located proximate the desired aircraft for refueling the aircraft. This is different from typical automobile fuel dispensers that are static and are not transported on trucks or other vehicles. As a result, fuel tanks used to provide fuel to automobile fuel dispensers are located separate from the fuel dispenser, typically beneath the ground. An example of a typical automobile fuel dispenser is described in U.S. Pat. Nos. 5,719,781 and 6,470,233, which are incorporated by reference herein in their entirety. However, a typical automobile fuel dispenser contains similar components and performs similar functionalities to dispenser fuel delivery vehicle 10 with an onboard fuel dispenser assembly 12.
Conventional fuel delivery vehicles 10 may typically fully integrate the fuel delivery assembly 12 into the chassis 14. In this regard, referring now to FIG. 1B, a schematic diagram of the fuel delivery assembly 12 of the conventional fuel delivery vehicle 10 is described. In this conventional arrangement, the entire fuel delivery assembly 12 is mounted onto the chassis 14 of the fuel delivery vehicle 10. The fuel delivery assembly 12 includes a hydraulic pump 16 installed on the chassis 14. A power take-off (PTO) 18 in mechanical communication with a chassis transmission 20 drives the hydraulic pump 16, thereby converting mechanical energy generated by a vehicle engine 22 of the chassis 14 into hydraulic energy. The hydraulic energy is used to drive a hydraulic motor 23, which causes fuel 24 to be pumped by product pump 25 at a rate that is directly proportional to the throughput of the hydraulic pump 16.
The operating speed of the hydraulic pump 16 is also directly proportional to the speed of the vehicle engine 22. Accordingly, the conventional method for changing the flow rate of fuel 24 with a conventional vehicle fuel delivery chassis 12 is to vary the rotational speed (i.e. RPM) of the vehicle engine 22, for example, via control interface 26 located for example in the vehicle cab 28.
This arrangement is limited in that the fuel delivery assembly 12 is generally designed to be permanently installed on the vehicle chassis 14 and thus requires specific design features for each type of vehicle chassis 14. This arrangement also requires the vehicle engine 22 to be continuously monitored and adjusted to maintain a substantially constant flow rate of the fuel 24. Accordingly, there is a need in the art for a more versatile aircraft refueling system.